Indicating wheel driving mechanisms of timepieces

ABSTRACT

In an indicating wheel driving mechanism of a timepiece, comprising an indicating wheel driving wheel and an indicating wheel driving wheel finger for driving said driving wheel, a slot is formed in the driving wheel to define a resilient portion and said indicating wheel driving wheel finger is formed integrally with said resilient portion at a location adjacent the free end thereof, and further means for restricting the degree of bending of said resilient portion is provided, whereby when the driving wheel rotates in the normal direction, the resilient portion is prevented from bending and an indicating wheel is driven by said finger, whereas when the driving wheel rotates in the reverse direction, the resilient portion is allowed to bend and the finger is relieved from restraint by the indicating wheel, providing for rotation of said driving wheel.

11 3,744,237 [45] July 10,1973

[ INDICATING WHEEL DRIVING MECHANISMS OF TIMEPIECES [75] Inventor: TeruoMuto, Kita-ku, Tokyo, Japan [73] Assignee: Citizen Watch Co., Ltd.,Tokyo,

Japan [22] Filed: Mar. 1, 1972 [21] App]. No.: 230,572

[30] Foreign Application Priority Data Mar. 4, 1971 Japan 46/13861 [52]US. Cl. 58/58 [51] Int. Cl. ..L G04b 19/24 [58] Field of Search, 58/4,5, 58, 63

[56] References Cited UNITED STATES PATENTS 3,352,103 11/1967 Giger58/58 3,177,647 4/1965 Meyer 58/58 FOREIGN PATENTS OR APPLICATIONS420,996 3/ 1967 Switzerland 58/58 480,674 12/1969 Switzerland 515/58Primary Examiner--George H. Miller, Jr. Att0rneyS. Delvalle Goldsmith,Lester Horwitz et a1.

[57] ABSTRACT In an indicating wheel driving mechanism of a timepiece,comprising an indicating wheel driving wheel and an indicating wheeldriving wheel finger for driving said driving wheel, a slot is formed inthe driving wheel to define a resilient portion and said indicatingwheel driving wheel finger is formed integrally with said resilientportion at a location adjacent the free end thereof, and further meansfor restricting the degree of bending of said resilient portion isprovided, whereby when the driving wheel rotates in the normaldirection, the resilient portion is prevented from bending and anindicating wheel is driven by said finger, whereas when the drivingwheel rotates in the reverse direction, the resilient portion is allowedto bend andthe finger is relieved from restraint by the indicatingwheel, providing for rotation of said driving wheel.

9 Claims, 6 Drawing Figures INDICATING WHEEL DRIVING MECHANISMS OFTIMEPIECES This invention relates to a driving mechanism in a timepieceof the type having an indicating wheel or wheels such as a date dial, bywhich said indicating wheel is driven to change the indication thereof.

Conventional indicating wheel driving mechanisms of the type describedinclude a type which comprises a driving wheel and a finger for drivingsaid driving wheel fixed on a gear, and a type which comprises a drivingwheel, a finger for driving said driving wheel rotatably mounted on agear and spring yieldably holding said finger in engagement with saiddriving wheel in such a manner that said driving wheel may be rotatableat the time of reverse rotation of the indicating wheel or quickcorrection of indication. However, the former type has the disadvantagethat, when the finger is in engagement with the tooth of the indicatingwheel at the time of reverse rotation or quick correction of indication,it cannot be relieved from restraint by the indicating wheel, with theresult that the indication cannot be changed sequentially or theindicating wheel cannot be driven, and the application of unreasonableforce to the driving mechanism tends to result in breakage of themechanism. The latter type is free of the abovedescribed disadvantagebut suffers such disadvantage that the mechanism is complicated andincludes an undesirably large number of component parts such as thefinger, the spring, the pivot pin for the finger, etc. which are verysmall in size and'hence difficult to fabricate and assemble.Furthermore, in both types the gear and finger are substantially largein thickness and occupy a considerably large space, it being impossibleto reduce said thicknesses even when it is most desirable to arrange theteeth of the indicating wheel and driving wheel on the same level. Anadditional disadvantage of these prior art driving mechanisms is thatthe clearance between the pivot pin of the finger, provided on the gearand a hole for receiving said pin formed in said finger must becontrolled with high precision.

The present invention contemplates the elimination of such disadvantagesof the prior art mechanisms. Namely, the object of the invention is toprovide an indicating wheel driving mechanism of a timepiece, whichsatisfies the following requirements:

a. The indicating wheel driving wheel finger can be smoothly relievedfrom the indicating wheel at the time of reverse rotation of the drivingwheel and quick correction of indication by a quick correctionmechanism,

b. The construction is simple.

The above object can be attained by an indicating wheel drivingmechanism which comprises an indicating wheel driving wheel having aslot formed therein to define an integral resilient portion, anindicating wheel driving wheel finger formed integrally with saiddriving wheel at a location adjacent the free end of said resilientportion for engagement with the teeth of indicating wheel and means forrestricting the degree of bending of said resilient portion, saidbending restricting means preventing bending of said resilient portionduring rotation of said driving wheel in the normal direction butpermitting the bending of said resilient portion during reverse rotationof said driving wheel so that said driving wheel finger may be relievedfrom restraint by the teeth of said indicating wheel.

The present invention will be described by way of example hereunder withreference to the accompanying drawings. In the drawings,

FIG. 1 is a plan view showing the essential portion of a firstembodiment of the indicating wheel driving mechanism according to thepresent invention, as applied to a calender timepiece for driving a datedial, a dial and a date dial guard being not shown for the sake ofsimplicity;

FIG. 2 is a sectional view taken on the line IIII of FIG. 1;

FIG. 3 is a plan view similar to FIG. 1 but showing the essentialportion of a second embodiment of the invention;

FIG. 4 is a sectional view taken on the line IVIV of FIG. 3;

FIG. 5 is a plan view similar to FIGS. 1 and 3 but showing the essentialportion of a third embodiment of the invention; and

FIG. 6 is a sectional view taken on the line VI-VI of FIG. 5.

With reference to the drawings and first to FIGS. 1 and 2, a drivingwheel 3 loosely rotatably mounted on a pin 1a on a plate 1 has aresilient portion 3c defined by a substantially elongated slot 3b formedtherein. The driving wheel 3 is formed from a singular planar gear blankand has teeth 3d continuously formed along the peripheral edge thereofincluding the resilient portion 3c, and the tooth 3e located adjacentthe free end of said resilient portion 30 is made longer than theremaining teeth 3d to constitute an indicating wheel driving wheelfinger. The tooth 3e otherwise has the same function as the teeth 3d.Bending check portions 3f, 3g are provided at the free end of theresilient portion 3c and the confronting portion of the main portion orbody 3a of the driving wheel 3 respectively, as means for restrictingthe degree of bending of said resilient portion 30, which abut againsteach other during rotation of the driving wheel 3 in the normaldirection. On an hour wheel 4 is mounted an intermediate wheel 5 whichis meshing with the driving wheel 3. An indicating wheel or date dial 2has teeth 2a and is arranged such tht said teeth 2a may be engaged bythe indicating wheel driving wheel finger 3e of the driving wheel 3.Reference numeral 6, in the embodiment shown, designates a date dialguard which in this case is an indicating wheel guard, 7 a dial, 8 adial jumper and 9 a cannon pinion.

The driving mechanism constructed as described above operates in thefollowing manner: Namely,'when it is desired to drive the indicatingwheel 2, the driving wheel 3 is rotated counterclockwise by theintermediate wheel 5 rotating in a clockwise direction and theindicating wheel driving wheel finger Se is brought into engagement withthe tooth 2a of indicating wheel 2. As the indicating wheel drivingwheel finger 3e moves further in engagement with the tooth 2a, theresilient portion 3c is bent more and more, and finally the bendingcheck portion 3f is brought into abutment with a surface of the bendingcheck portion 3g of the main portion 3a of driving wheel 3. Therefore,the resilient portion 3c is prevented from further bending and causesthe indicating wheel 2 to be rotated one tooth in a counterclockwisedirection by the indicating wheel driving wheel finger 32 which can nolonger be displaced either radially or circumferentially relative to themain gear body 3a. Thus, the indication, such as date, on the indicatingwheel is changed.

When it is desired to further change the indication to the next date, astern (not shown) of the timepiece is rotated in the opposite directionto the former direction, whereby the intermediate wheel is rotated in acounterclockwise direction, the driving wheel 3 is rotated in aclockwise direction and the indicating wheel driving wheel finger 3eengages the tooth 2a of indicating wheel 2. Therefore, the resilientportion 30 of the driving wheel 3 is bent more and more as said drivingwheel 3 rotates and finally the indicating wheel driving wheel finger 3ejumps over the tooth 2a of indicating wheel 2. During this period, theindicating wheel 2 is held stationary in its position.

Now, when the rotating direction of the stem is changed, the mechanismoperates in the same manner as in the case of clockwise rotation of theintermediate wheel 5 described previously. Namely, the intermediatewheel 5 rotates clockwise causing the driving wheel 3 to rotate in acounterclockwise direction, and the indicating wheel driving wheelfinger Se is brought into engagement with the tooth 2a of indicatingwheel 2 and drives said indicating wheel one tooth. Thus, the indicationis changed. Quick correction of date on the indicating wheel 2 can beachieved in this manner.

The indicating wheel driving wheel finger 3e will not be broken even ifit is at the position of the teeth 2a of indicating wheel 2 at, the timeof quick correction of date by means of a quick correction mechanism(not shown), since it is relieved from restraint by the indicatingwheel, due to the resiliency of the resilient portion 3c.

The embodiment described above is advantageous in that, since thebending check portions for restricting the degree of bending of theresilient portion are provided on the driving wheel proper, noadditional parts need to be provided for the same purpose.

The second embodiment of the invention will be described with referenceto FIGS. 3 and 4 in which parts corresponding to those of the firstembodiment are indicated by same numerals with 100 added thereto. inH08. 3 and 4, reference numeral 101 designates a plate having adepression 101b, 102 an indicating wheel, for example, date dial havingteeth 102a, and 103 a driving wheel loosely rotatably mounted on a pin101a on the plate 101 and having a resilient portion 1030, defined by asubstantially elongated slot 103b, and an indicating wheel driving wheelfinger 103s adjacent the free end of said resilient portion forengagement with the teeth 102a of said indicating wheel 102, similar tothe driving wheel of the first embodiment. Reference numeral 105designates an intermediate wheel mounted on an hour wheel 104 andmeshing with the teeth 103d of the driving wheel 103. In thisembodiment, the depression 1011b formed in the plate 101 is so shapedthat the wall of said depression will restrict the degree of bending ofthe resilient portion 103cdriving wheel 103. j

in the construction described above, when the intermediate wheel 105rotates in the normal direction, the driving wheel 103 is rotated andits finger 103a is brought into abutment against the tooth 102a of theindicating wheel 102. As the driving wheel 103 further rotates, theresilient portion 103a bends but the bending is restricted by a stopsurface on the wall 1010 of the depression 101b formed in the plate 101and said finger 103e causes the indicating wheel 102 to rotate. In themechanism according to this embodiment, the

component parts operates in the same manner as those in the firstembodiment at the time of reverse rotation of the driving wheel 103 andquick correction of indication by a quick correction mechanism (notshown).

According to this embodiment, the following advantages can be obtained:

a. Since the driving wheel and indicating wheel are arranged not in thesame plane, less limitation is imposed on the shape of driving wheel,which facilitates the design of the timepiece mechanism. For instance,when a date dial in the form of a ring having internal teeth, like thatof the first or second embodiment is employed, a driving wheel of alarge diameter is required for driving said date dial by reason ofreduction gear ratio, but according to this embodiment such a largediameter driving wheel can be arranged more easily than in the firstembodiment, as it can be disposed beneath the indicating wheel.

b. Since the wall of the depression in the plate is utilized forrestricting the degree of bending of the resilient portion, noadditional parts are required for the same purpose.

A third embodiment of the invention is shown in FIGS. 5 and 6 in whichparts generally corresponding to those of the first embodiment areindicated by same numerals with 200 added thereto. in FIGS. 5 and 6,reference numeral 201 designates a plate and 202 an indicating wheel forindicating date having teeth 202a. The teeth 202a of the indicatingwheel 202 are held down by a date dial guard 206 secured to the plate201 by means of a screw 207. The date dial guard 206 has an integraldate jumper 206a at one end thereof and also has a cam shaped recess206b formed therein at a location above a driving wheel to be describedlater. Reference numeral 203 indicates the driving wheel which isloosely rotatably mounted on a pin 201a on the plate 201 and has aresilient portion 203e, defined by a substantially elongated slot 203b,and teeth 203d continuously formed along the peripheral edge thereof,one of said teeth 203d which is located adjacent the free end of saidresilient portion 203c being made longer than the remaining teeth toconstitute an indicating wheel driving wheel finger 203e, for drivingthe indicating wheel 202, similar to the driving wheel of the first orsecond embodiment described above. In this embodiment, however, aprojection 203f is provided on the upper surface of the resilientportion 2030 of driving wheel 203 at a location adjacent the free end ofsaid resilient portion 203C, and this projection 203 f extends intoengagement with the surface of the cam shaped recess 206!) of date dialguard 206. On the other hand, the driving wheel 203 is meshing with anintermediate wheel 205, mounted on an hour wheel 204, to be driventhereby.

[n the construction described above, when the driving wheel 203 isrotated in the normal or reverse direction, the degree of engagementbetween the indicating wheel driving wheel finger 203e and the tooth202a of indicating wheel 202 can be adjusted by the co-action of theprojection 203f on the resilient portion 201% and the cam shaped recess206b, so that the indicating wheel 202 can be driven exactly.Furthermore, quick correction of indication by a quick correctionmechanism (not shown) can be smoothly achieved even if the finger 203eis at the position of the teeth 202a of indi cating wheel 202, becausethe finger 203e is relieved from restraint by the indicating wheel 202,due to the resiliency of the resilient portion 203c.

According to this embodiment, the following advantage can be obtained:Namely, since the degree of bending of the resilient portion and thedegree of engagement between the indicating wheel driving wheel fingerand the tooth of indicating wheel can be adjusted by the cam shapedrecess, the indicating wheel can be positively driven.

In summation, the driving mechanism of the invention has the followingadvantages over the prior art mechanisms:

a. The driving wheel, because of its simple shape, can be integrallymolded of a synthetic resin material and, therefore, is economical andnot required to be assembled, as compared with that in the prior artmechanism which is composed of a plurality of parts.

b. The resilient portion can be made highly flexible as it can be madeconsiderably long as required. Therefore, it passes over the tooth ofindicating wheel very easily, without exerting an unnecessary reactionon the indicating wheel, and there is no fear of the indicating wheelbeing displaced from its set position. Consequently, the strength of thejumper can be decreased and hence the indicating wheel can be drivenwith a minimum load.

c. The bending degree of the resilient portion is restricted by thebending check means, so that in no cases will the indicating wheeldriving wheel finger be moved off the position to engage the tooth ofindicating wheel during rotation of said indicating wheel in the normaldirection and positive driving of the indicating wheel is ensured.

What is claimed is:

1. An indicating wheel driving mechanism in a time piece, comprising anindicating wheel driving wheel having a slot formed therein to define anintegral resilient portion, an indicating wheel driving wheel fingerformed integrally with said driving wheel at a location adjacent thefree end of said resilient portion for engagement with the teeth ofindicating wheel, and means for restricting the degree of bending ofsaid resilient portion, said bending restricting means preventingbending of said resilient portion during rotation of said driving wheelin the normal direction, but permitting the bending of said resilientportion during reverse rotation of said driving wheel so that saidindicating wheel driving wheel finger may be relieved from restraint bythe teeth of said indicating wheel, said means for restricting thedegree of bending consisting of the wall of a depression formed in aplate of the timepiece and said resilient portion being brought intoabutment against said wall, whereby the degree of bending of saidresilient portion is restricted.

, 2. An indicating wheel driving mechanism in a timepiece, comprising anindicating wheel driving wheel having a slot formed therein to define anintegral resilient portion, an indicating wheel driving wheel fingerformed integrally with said driving wheel at a location adjacent thefree end of said resilient portion for engagement with the teeth ofindicating wheel, and means for restricting the degree of bending ofsaid resilient portion, said bending restricting means preventingbending of said resilient portion during rotation of said driving wheelin the normal direction, but permitting the bending of said resilientportion during reverse rotation of said driving wheel so that saidindicating wheel driving wheel finger may be relieved from restraint bythe teeth of said indicating wheel, said means for restricting thedegree of bending consisting of a projection formed on the upper surfaceof said resilient portion integrally therewith and a driving wheel guardhaving a cam shaped recess formed therein, and said projection beingbrought into abutment against the edge of said cam shaped recess,whereby the degree of bending of said resilient portion is restricted.

3. In a timepiece having an indicator and a driving mechanism foradvancing the indicator in one direction between a plurality ofindicating positions, a driving wheel comprising a planar gear bodyhaving a periphery formed with a plurality of teeth in meshingengagement with said driving mechanism, said gear body being providedwith an elongated slot to form a resilient peripheral portion of saidgear body having a deflectable end from which one of said teeth project,a driving formation projecting from said deflectable end of theresilient portion and engageable with the indicator, and deflectionlimiting means for preventing radial and circumferential displacement ofsaid driving formation relative to the gear body in response toengagement thereof with the indicator in said one direction only.

4. The combination of claim 3 wherein said driving formation is a radialextension of said one of the teeth at the deflectable end of theresilient portion of the gear body.

5. The combination of claim 4 wherein said deflection limiting meansincludes a projection on the resilient portion adjacent the deflectableend and a stop surface engageable by the projection in response todisplacement of the driving formation when engaging the indicator.

6. The combination of claim 5 wherein said stop surface is on a fixedcam member.

7. The combination of claim 3 wherein said deflection limiting meansincludes a projection on the resilient portion adjacent the deflectableend and a stop surface engageable by the projection in response todisplacement of the driving formation wihen engaging the indicator.

8. The combination of claim 7 wherein said stop surface is formed on acheck portion of the gear body.

9. The combination of claim 8 wherein said driving formation is a radialextension of said one of the teeth at the deflectable end of theresilient portion of the gear body.

1. An indicating wheel driving mechanism in a timepiece, comprising anindicating wheel driving wheel having a slot formed therein to define anintegral resilient portion, an indicating wheel driving wheel fingerformed integrally with said driving wheel at a location adjacent thefree end of said resilient portion for engagement with the teeth ofindicating wheel, and means for restricting the degree of bending ofsaid resilient portion, said bending restricting means preventingbending of said resilient portion during rotation of said driving wheelin the normal direction, but permitting the bending of said resilientportion during reverse rotation of said driving wheel so that saidindicating wheel driving wheel finger may be relieved from restraint bythe teeth of said indicating wheel, said means for restricting thedegree of bending consisting of the wall of a depression formed in aplate of the timepiece and said resilient portion being brought intoabutment against said wall, whereby the degree of bending of saidresilient portion is restricted.
 2. An indicating wheel drivingmechanism in a timepiece, comprising an indicating wheel driving wheelhaving a slot formed therein to define an integral resilient portion, anindicating wheel driving wheel finger formed integrally with saiddriving wheel at a location adjacent the free end of said resilientportion for engagement with the teeth of indicating wheel, and means forrestricting the degree of bending of said resilient portion, saidbending restricting means preventing bending of said resilient portionduring rotation of said driving wheel in the normal direction, butpermitting the bending of said resilient portion during reverse rotationof said driving wheel so that said indicating wheel driving wheel fingermay be relieved from restraint by the teeth of said indicating wheel,said means for restricting the degree of bending consisting of aprojection formed on the upper surface of said resilient portionintegrally therewith and a driving wheel guard having a cam shapedrecess formed therein, and said projection being brought into abutmentagainst the edge of said cam shaped recess, whereby the degree ofbending of said resilient portion is restricted.
 3. In a timepiecehaving an indicator and a driving mechanism for advancing the indicatorin one direction between a plurality of indicating positions, a drivingwheel comprising a planar gear body having a periphery formed with aplurality of teeth in meshing engagement with said driving mechanism,said gear body being provided with an elongated slot to form a resilientperipheral portion of said gear body having a deflectable end from whichone of said teeth project, a driving formation projecting from saiddeflectable end of the resilient portion and engageable with theindicator, and deflection limiting means for preventing radial andcircUmferential displacement of said driving formation relative to thegear body in response to engagement thereof with the indicator in saidone direction only.
 4. The combination of claim 3 wherein said drivingformation is a radial extension of said one of the teeth at thedeflectable end of the resilient portion of the gear body.
 5. Thecombination of claim 4 wherein said deflection limiting means includes aprojection on the resilient portion adjacent the deflectable end and astop surface engageable by the projection in response to displacement ofthe driving formation when engaging the indicator.
 6. The combination ofclaim 5 wherein said stop surface is on a fixed cam member.
 7. Thecombination of claim 3 wherein said deflection limiting means includes aprojection on the resilient portion adjacent the deflectable end and astop surface engageable by the projection in response to displacement ofthe driving formation when engaging the indicator.
 8. The combination ofclaim 7 wherein said stop surface is formed on a check portion of thegear body.
 9. The combination of claim 8 wherein said driving formationis a radial extension of said one of the teeth at the deflectable end ofthe resilient portion of the gear body.